


Castiel, Arachnid of the Lord

by superhoney



Category: Supernatural
Genre: Accidental Voyeurism, Animal Transformation, Canon Compliant, Cuddling & Snuggling, Fluff and Crack, Getting Together, Implied Sexual Content, It's weirdly sweet, M/M, Masturbation, Season/Series 12, Spells & Enchantments
Language: English
Status: Completed
Published: 2017-08-07
Updated: 2017-08-07
Packaged: 2018-12-12 10:01:59
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 9,597
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11734746
Author URL: https://archiveofourown.org/users/superhoney/pseuds/superhoney
Summary: The one in which Cas gets turned into a spider and Dean finds himself oddly grateful to an incompetent witch.





	1. Chapter 1

**Author's Note:**

> You can blame the entire Tropefest chat but mostly Ri, Cat, and Diamond for this one. 
> 
> Thank you especially to Diamond for the beta-read, the encouragement, and the art you'll find at the end of the story.
> 
> And thank you, Anna, for reading this despite your initial proclamation that spider fic might be taking it too far.

There’s a spider in the corner of Dean’s room.

They don’t normally get many bugs in the Bunker. Apparently the warding that keeps the supernatural beings out also works on household pests. Dean stares at it for a second, his lip curling up in distaste. It’s large enough that he can see it clearly even from a distance, stark against the pale walls.

Dean keeps a clean house. A clean room. It offends him to suddenly see this intruder, this gross little thing, occupying his space. But he and Sam just got home from a particularly exhausting vampire hunt, and though he’d never admit it to anyone, Dean is tired of killing things.

“It’s your lucky day,” he tells the spider. “But if you’re still here in the morning, we’re going to have a problem.”

The spider doesn’t reply. Of course it doesn’t. It’s a spider. 

Dean snorts to himself. That hunt really took a lot out of him. Stripping off his jeans, he tosses them to the ground, then adds his plaid overshirt and plain black t-shirt to the pile. He’s already letting things go to shit around here, what’s a little bit of laundry on the ground?

In just his boxers, he climbs into bed and moves to turn off the light. He casts a wary look up at the spider, which seems to have curled in on itself, maybe sensing Dean’s movements and trying to make itself appear smaller out of a sense of self-preservation. 

“Good night, Westley,” he mutters. “Good work. Sleep well. I’ll most likely kill you in the morning.”

God, he really needs sleep. He’s being absolutely ridiculous right now. But like every other night, he checks his phone one last time first. No new messages, it tells him. 

He drums his fingers on its surface a few times. He hasn’t seen Cas in a few days, not since before he and Sam left on this last case. He knows Cas is busy, off doing his own thing, and that he’s perfectly capable of handling himself, but Dean worries. So he sends him a quick message: _Hey, you doing okay?_ and puts the phone away. 

He falls asleep hoping to hear it chime back with a reply, but it never does.

***

He doesn’t think about it the next morning, stumbling out of his room shortly after seven without even turning on the light. After a quick shower, he returns to his room, and that’s when he sees the large web stretched across the corner of the room.

“Oh, hell no,” he declares, and goes to get a broom.

Of course, the second the broom makes contact with the web, the spider goes scurrying off across the ceiling, and of course, it heads right towards Dean, who absolutely does not yelp and drop the broom as he takes a startled step back. 

Absolutely not.

“Good morning to you too,” he says under his breath as he picks the broom back up. “Little bastard.” With the spider out of the way, he clears the web from the ceiling, looking at it in distaste. “Just had to go and make a mess all over the place, didn’t you.”

The spider is frozen in place on the middle of the ceiling. Dean looks at it and sighs. He still doesn’t really feel like killing anything, but he also doesn’t want to be cleaning cobwebs from his room every morning.

“Sorry,” he says as he smacks the broom in the spider’s general direction. It’s quick, though, taking off across the ceiling too fast for him to catch it. He chases it around for a few minutes, but it manages to avoid his reach every time. 

“You’re stubborn, I’ll give you that,” he tells it, hands on his hips as he looks up at it. “Got a strong will to live. I respect that. So why don’t you come a little closer, and I won’t hit you with the broom. I’ll just take you outside, let you loose, and go double-check our warding.”

“Who are you talking to?” Sam peers into the room through the open door, dressed for a run. 

Feeling himself flush faintly, Dean mumbles, “No one.”

Sam just raises an eyebrow at him.

“The spider,” Dean admits, pointing upwards. 

“Jesus,” Sam says, taking an involuntary step back. “That thing is huge.”

It is rather large, now that Dean is looking at it with well-rested eyes. Bigger than any spider he’s seen indoors before. 

Of course, Sam is curious about it. He moves cautiously into the room, keeping his eyes fixed on the spider on the ceiling. “Maybe it was down in one of the store-rooms somewhere and made its way here?” he suggests. “I don’t think spiders that big are native to Kansas.”

“Why’d it have to pick my room?” Dean complains. “There are what, a dozen other empty rooms in this place? Why mine?”

Sam doesn’t answer, too busy scrolling through images on his phone. “I don’t think it’s poisonous or anything.”

“I still don’t want it in my room.”

“Fine,” Sam sighs. He crouches down and reaches under Dean’s bed, pulling out the shoebox he uses to store his porn magazines in and dumping its contents over Dean’s bed without even blinking.

“Hey,” Dean protests, but Sam ignores him. How did he even know that was there? Dean scowls at him as Sam positions himself under the spider, and using the extra two inches of his height to his advantage, tries to scoop the spider into the box. 

It scurries away again.

Dean is oddly enjoying watching his brother struggle. “It’s a weaselly little thing,” he says, only slightly condescending. “Not so little, but you get my point.”

The spider has made its way to the other side of the room and is curled into a tiny ball right where the wall meets the ceiling. It’s going to be impossible to reach in that position.

“Just leave it for now,” Sam advises. “Either it’ll disappear on its own, or it’ll come down eventually.”

“You wouldn’t say that if it were in your room,” Dean mutters. 

“What, are you scared of it or something?” There’s a gleeful look on Sam’s face, like he can’t believe his tough-as-nails brother is freaked out by something as ordinary as a spider, even one this big.

“No,” Dean lies. “I just don’t want it making any more webs in my room.”

“Sure,” Sam says, clearly not convinced. “I’m going for a run. You stay here and hang out with your new roommate.”

Dean flips him off as he walks away. Traitor. 

He glances up at the spider again, still curled in on itself in the corner of the room, and sighs. He isn’t going to be able to stay in here with it watching him, and now that Sam’s gone for at least an hour, he won’t make fun of Dean for fleeing. 

“You suck,” he informs it as he leaves his room.

***

Dean is not avoiding his bedroom. He just has a lot of research to do. Those British Men of Letters are a sneaky bunch, and he’s positive there must be more about them in the Bunker’s files. All of which happen to be kept places other than his room.

Sam gets back from his run, snorts at Dean, and strides off towards the showers without a word. Dean watches him go, shaking his head. Not even a disparaging remark about his usual aversion to research? Sam must have used up all his energy on his exercise routine. 

He turns back to his files, and that’s when he sees it.

That goddamn spider, climbing determinedly up the leg of the table.

“What the fuck,” Dean says, pushing his chair away. Either the noise or the vibration must startle the thing, because it pauses for a second before continuing on its path.

Dean’s starting to freak out a little bit, here. Is this thing _following_ him? It can’t be. Can it?

It makes it to the top of the table and scuttles towards him. Dean still doesn’t really want to kill it, but it’s making him really uncomfortable. He grabs the box of files he’d been looking through, dumps the contents on the floor, and hastily tosses the box over the spider.

Out of sight, out of mind, right?

Not so much. Dean keeps sneaking glances at the box as he tries to return to his research. It’s a damn big spider. What if it manages to move the box somehow? 

Sam comes back in, takes one look at the box, and goes to move it so he can sit down.

“No!” Dean exclaims, throwing out a hand to stop him.

“What?” They each have a hand hovering over the box, and Sam’s drops first. 

“The spider’s under there,” Dean mumbles, not meeting Sam’s eyes. So maybe he’s a bit embarrassed that he hasn’t just killed the thing already. He hunts monsters, for Christ’s sake, has done for years. But one measly not-so-little spider, and he goes soft? Pathetic.

Sam, to his credit, doesn’t laugh at him. He just nods. “Are you trying to suffocate it?”

“What? No,” Dean replies, shocked. If he was going to kill it, he’d at least have the guts to do it properly.  
“Then you’re going to want to cut some air holes in the box,” Sam explains. “Is it our pet now? You won’t let me have a dog, but a spider is okay?”

“Shut up.” Dean digs his knife out of his pocket and carefully pokes a few holes in the top of the box, none big enough for the spider to escape through. “Besides, apparently the pet adopted us in this situation. I swear it’s attached to me or something. Followed me in here, climbed right up towards me.”

“That is strange.” Sam looks at the box thoughtfully. “I’ll look into it.” He grabs a few books off the shelf and leaves the room, probably headed for his own, spider-free bedroom.

“Look into what?” Dean calls after him, but Sam doesn’t reply.

“Well, it’s back to just you and me, then,” he says to the box.

He could swear it moves slightly, like the spider inside is responding to his voice. He’s mostly still freaked out, but there’s something oddly endearing about the whole idea.

“Gonna have to think up a name for you,” he muses. “Something cool. Something badass.” He thinks about it for a moment. “How do you feel about Shelob?”

There’s no further movement from the box, so Dean turns back to his files, satisfied. It’s nice, having company while he works.

He leaves the box where it is throughout the day. But as time passes, he wonders how the thing will survive with no other bugs to snack on. He feels bad starving it, so he resolves to let it go. He slides a piece of paper underneath the box and carries the whole thing up the stairs and out the door, gently depositing it on the ground a few steps away from the Bunker’s entrance so he doesn’t accidentally step on it on his way back in.

“Bye, buddy,” he says, giving it a little salute. “You’ll do fine out here. You’ve got gumption.”

The spider doesn’t move, probably too confused by being outside again to scurry off right away. Dean takes one last look at it and turns away.

And that, he thinks as he pulls open the door, is the end of that.

***

As he’s getting ready for bed that night, Dean glances up at the corner where he first saw the spider and shakes his head, smiling to himself. It’s a good story. He thinks Cas would enjoy hearing it. He picks up his phone before he can second-guess himself and brings up Cas’ contact page, then hits call. The phone rings and rings and eventually goes to voicemail. Dean rolls his eyes fondly as Cas’ voice tells him to make his voice a mail.

“Hey, Cas, it’s me,” he says. “Just calling in to check in on you, haven’t heard from you in a few days. Give me a call when you get a chance.” 

He ends the call and puts the phone down, making sure the volume is turned up so he’ll hear it if Cas calls him back. He putters around for a few minutes, brushing his teeth and stripping down to his boxers, but there’s no reply from Cas. 

Should he call again? He doesn’t want to seem desperate, or clingy, or overbearing, even though he’s well-aware all three terms describe him fairly accurately. Cas must just be busy, he rationalizes. He would call if something serious was going on. 

Dean climbs into bed and picks his phone back up, thumbing through various news sites in case he catches wind of a possible case. Nothing jumps out at him, though, and he should really just try to get some sleep, but he feels oddly jittery, his mind not yet settled. 

Fortunately, years of experience have taught him how to handle this particular kind of restlessness. He drops his phone back on the nightstand and lets his hand trail slowly down his bare chest, tipping his head back with a contented sigh. It’s been a few days since he had the chance to touch himself like this, leisurely and self-indulgent. He slips his hand into his boxers and grips himself lightly, grateful as ever that the bedroom walls are thick enough to block out all his admittedly loud moans.

He imagines, not for the first time, what it would be like to have someone else touch him like this. So slow and sweet. Without even intending to, he lets his bitten-back sigh turn into something else, Cas’ name falling from his lips as he comes.

It’s not the first time, and he doubts it will be the last.

Once he recovers his breath, he wipes himself down with the tissues he keeps beside the bed and turns off the light, pulling the covers over himself. His mind is pleasantly fuzzy, his body relaxed from his orgasm, and it doesn’t take long for him to drift off to sleep. 

In the morning, he wakes up, checks his phone for messages, and frowns when he sees no new notifications. He’s grumpy and out of sorts, and he wants his Dead Guy Robe to cuddle up in. He turns on the lamp and swings his legs over the side of the bed, and that’s when he sees it.

Another web, in the exact same place as before, but this time, the words _Hello, Dean_ are crookedly but legibly spelled out across its centre. 

He lets out an ear-shattering shriek, and mere seconds later, Sam nearly knocks the door down as he bursts in with his gun drawn, hair wild and eyes even wilder.

“What?” he asks frantically. “What is it?”

Dean just points to the web with shaky fingers. 

Sam lowers his gun and walks towards it, still wary. “What the hell,” he murmurs. “Dean, how does it--”

“It’s not an it,” Dean says, amazed at how level his voice is. “It’s Cas.”

The spider is Cas. Cas is the spider. Dean doesn’t know how, and he doesn’t know why, but he just _knows_. 

The spider-- Cas, Dean reminds himself-- drops elegantly from his web to dangle before them, almost like he’s greeting them. He must have been trying to get Dean’s attention this whole time, following him to the library and getting right in his face like that. 

Oh God. And Dean tried to kill him. 

“I’m so sorry,” he blurts out. “I’m sorry I tried to hit you with a broom and I put you in a box and I left you outside, oh my god, I didn’t know it was you--”

“Wait,” Sam interrupts with a frown. “Even if it is Cas, how do we know he can understand us?”

Dean pauses, unsure. Sam’s right, they don’t know the extent to which Cas is affected by the spell or curse or whatever turned him into a spider in the first place. But before he can respond, Cas launches himself at Sam, landing directly in his hair.

It’s Sam’s turn to shriek, and Dean dissolves into self-satisfied laughter at the sight of him frantically trying to get Cas out of his hair while also not hurting him. It’s a mess of flailing limbs and silky locks turning to tangled knots. 

“You tell him, Cas,” Dean says approvingly once his laughter has subsided. “That’ll be the last time he doubts you.”

He reaches out his hand, no longer afraid now that he knows it’s just Cas, and Cas eventually leaps from Sam’s head onto Dean’s outstretched hand. If it was ever possible for a spider to look self-satisfied, it would look exactly like Cas right now. Dean resists the urge to stroke him fondly, settling instead for gently placing him on the dresser so he’s got a good view of the room. 

“Alright,” Sam says, smoothing his hair back into place as best as possible and looking properly chastened, “so you can understand us, Cas. But I’m guessing you can’t talk, otherwise you wouldn’t have had to resort to the trick with the web.”

“That’s some Charlotte’s Web-level shit right there,” Dean says admiringly. “Good job. But it’s gonna be a bitch to do that every time you need to communicate.”

Cas doesn’t move, which Dean takes as agreement. He purses his lips, then digs through his drawers for a marker and some sticky notes. He writes Yes on one and No on the other, then sticks them both to the wall underneath the web.

“Huh,” Sam remarks. “That’s a good start.”

Cas scuttles across the dresser and along the wall, perching on the paper that says Yes. Evidently, he approves.

“Okay, and he can read too,” Dean notes. “Awesome.”

“So, next, we should probably figure out exactly what happened, and how to get Cas back.” Dean can hear the excitement creeping into Sam’s voice now that he’s settled down, eager to get his nose in a book or five. 

“What do you think?” he asks Cas, who stays where he is.

“Cool,” Dean says. He stretches out his hand again, and Cas climbs elegantly onto his palm. It tickles, but he stays still once he’s there, so Dean is able to carry him without incident. 

He strides off jauntily down the hallway, humming to himself. “Spider-Cas, Spider-Cas…”

“You’re an idiot,” Sam informs him, but there’s a fond smile tugging at the corners of his lips.

“You’re just jealous you don’t get a theme song,” Dean shoots back, and keeps humming. “Has whatever a spider has…”

Cas told him he liked Dean’s singing, once. He wonders if that still holds true. It must be scary, being so tiny all of a sudden. If singing stupid songs has even the slightest chance of making Cas feel better, Dean will sing his little heart out. 

They get themselves set up in the library. Now that they’re aware of his situation, Cas seems bolder, clambering around the table and shelves with impressive speed and dexterity. He pauses on volumes that look promising as Sam follows behind him, dutifully removing the relevant books from the shelves and stacking them on the table. 

By the time they’re done, there are at least twenty books piled in the centre of the table. “You have got to be kidding me,” Dean mutters.

Cas scurries over to join him, perching right beside Dean’s hand as though waiting for him to open a book. “Alright, buddy,” Dean sighs. “Let’s do this.”

After three hours, the stack of books has dwindled slightly, but that’s the only progress they’ve made. They’ve gone through three pots of coffee and a few beers each, and still no luck. There are some basic descriptions of animal transformation spells in a few of the books, but they’re all only meant to last a few hours, and Cas has been a spider for a lot longer than that. 

“I wish you could tell us what happened,” Sam says, rubbing wearily at his eyes. “Not that I’m blaming you or anything, Cas.”

“Yeah,” Dean says with a frown. “How come you can still read, but you can’t talk? Weird.”

Cas looks slightly abashed, curling in on himself like somehow his inability to communicate is his fault. “Oh, hey, no,” Dean protests. “We’re gonna figure this out, okay? I promise.”

He grabs a few pieces of paper from his notebook and repeats the process from earlier, writing Yes on one and No on the other, then adds Maybe and Don’t Know for good measure. 

“Okay,” he says, “let’s try this again. Do you know who cursed you?”

Cas immediately dashes to the No paper and stays there. 

“Great,” Sam mutters. “Okay. What were you doing when you got cursed? Sorry. That won’t work. Uh. Were you alone when you got cursed?”

Cas seems to hesitate for a minute before moving to Maybe. 

“Maybe alone?” Dean and Sam trade confused glances. “That doesn’t make sense.”

Cas runs over to Don’t Know, and then back to Maybe. 

“Maybe alone...don’t know if you were alone…” Sam muses. “You were alone but not alone?”

That’s a yes.

“Okay, like in a public place? You were by yourself, but there were other people around?” Dean asks.

Cas stays where he is. 

“Bold move,” Sam comments. “Cursing someone in public like that.”

“Stupid move,” Dean corrects before being struck by a sudden thought. “What if it was an accident?”

Sam catches on quickly. “Like they meant to hit someone else and missed, and Cas just got unlucky?”

“Exactly.”

“Makes more sense than someone turning Cas into a spider on purpose.”

Sam’s right. But if the person casting the spell was sloppy enough to have it affect the wrong person, there’s a good chance they aren’t exactly going to be an expert, which doesn’t bode well for them being able to undo the curse.

Nevertheless… ”We have to find out who did this,” Dean says. “But I have no idea where to start.”

“Can we try to find Cas’ phone? Wherever it is, that must be the place he was when he got cursed. Cas, when the curse hit-- did you just turn into a spider right away, or did it take time to affect you?” Sam asks.

Cas moves off the paper and towards Sam, then stays still. Dean watches him with a frown, then sighs. “Sam, that was two questions in one. He doesn’t know how to answer clearly.”

“Right, yeah, sorry. Okay. Did you turn into a spider right away?”

Cas immediately scrambles over to the No paper. 

“How long would you say it took before you felt it? Less than an hour?”

He moves to Yes.

“But you knew something was wrong, you just didn’t know what?”

Cas stays where he is.

“So if that were me,” Sam says thoughtfully, “I’d go back somewhere safe. Somewhere private. Your motel?”

Cas’ legs move but he remains on the Yes paper, like he’s agreeing vehemently.

“Cool,” Dean says with a grin. “So we should be able to get the location of your phone from your cell company and that should lead us to your motel, at least.”

He stops, struck by a sudden thought. “How did you even get here, anyway? Last time we talked you were in Washington, and even if you were on your way here, there’s no way you were close enough to….walk, or whatever.”

“Yes or no questions,” Sam reminds him, like he didn’t just mess up in exactly the same way. Dean gives him a glare but then turns back to Cas, who’s hovering between the sheets of paper.

“Never mind,” Dean says with a sigh. “We can get the whole story once you’re, you know, _you_ again. Let’s focus on that.”

All this investigating is making Dean hungry. And speaking of food…

“Do you need to eat?” he wonders, frowning down at Cas. He really hopes the answer is no, because there aren’t any other creepy-crawlies in the Bunker for him to snack on. Not that Dean wouldn’t go find a few outside to make sure Cas is fed, but still. 

Cas darts over to the No paper, fortunately, and Sam lets out an audible sigh of relief. “Must be part of the spell,” he muses. “Some remnant of your Grace, maybe, keeping you from needing sustenance.”

“Cool,” Dean says. “I, however, do need sustenance. You keep digging on that motel, Sam. I’ll make us some sandwiches.”

Once he’s in the kitchen and out of sight, Dean slumps against the counter and rubs his hand over his face. God, he really hopes they can pull this off. It must be awful for Cas, stuck in that tiny body. Dean’s not an idiot. He knows Cas hates feeling useless, feeling like baggage, and he knows sometimes he contributes to that. He swears to himself not to let Cas feel like he’s just a problem to be solved this time. 

He doesn’t want to bring Cas back to normal because he’s more useful to him that way, or because he’s mad that they’re being inconvenienced or anything like that.

He just wants Cas back. Wanted him back here at the Bunker even before he knew about the curse. 

The sandwiches are done, and Dean can’t dwell on this any longer. He has to work to make it happen. He brings the plate back to the library and smiles when Cas creeps closer to him as soon as he sits down. He places his free hand on the table and lets Cas climb over his fingers as he eats, peering over Sam’s shoulder as he hacks into the phone company’s website. 

After a few minutes of Sam typing away on his laptop, he lets out a triumphant shout. “Got it,” he says. “Cheyenne. Motel Linden.”

Dean curses under his breath. It’s a six hour drive to Cheyenne. It’s too late to leave today, so they’ll have to wait until morning. And besides--

“What are we supposed to do with him?” he says, jerking his thumb towards Cas, still perched innocently on the table before him. “We can’t just leave him here.”

Dean swears he can see Cas glaring at him, which is particularly creepy since he’s sporting several extra eyes at the moment, before launching himself forward and running nimbly up Dean’s arm and tucking himself under his collar.

“I don’t think that’s going to work,” Dean tells him. 

Cas crawls out from under his collar and onto his arm so Dean can look at him properly. He looks offended, if that’s even possible.

“You know how much we tend to get thrown around on hunts,” Dean explains. “Somebody slams me up against a wall and you don’t jump free in time? I’m not letting you get squashed or stepped on or whatever, Cas.”

Sam is smirking at him from across the table, but Dean just gives him a pleading look. “Back me up here, man.”

“He’s right,” Sam agrees after a moment. “It’s too risky. It won’t be efficient, since you won’t be with us to get the spell reversed right away, but we’ll find the witch, figure out what they did to you, and bring them back here to fix it if we have to.”

Cas scurries down Dean’s arm and plants himself firmly on the No paper. Eight legs instead of two and four times as stubborn as usual, Dean thinks to himself fondly. 

“What are you going to do about it,” he snorts. “You can’t stop us.”

Cas pauses for a second, then leaps back towards Dean, web spinning as he goes. With startling speed, there’s a strand of thin white web wrapping around Dean’s arm and the arm of the chair beneath it. 

“What the fuck,” Dean says. He tries to tug at it, but he can’t see where Cas is, and he doesn’t want to risk hurting him by accident.

Sam is smirking at him again, the traitor.

“So that’s your plan, huh,” Dean says. He has to admit, it’s a damn clever one. “Tie us to our chairs so we can’t leave without you.”

Cas’ tiny body appears over the edge of the chair, all eight eyes fixed firmly on Dean’s face.

God, he is so whipped.

“Fine,” he sighs. “How about this. The witch who cursed you-- was there any reason to believe they were hurting anyone? Killing anyone?”

Cas abandons his arm and runs back over to the No paper.

“Okay,” Dean says, pressing his fingers to his forehead. “So you probably got the worst of it. A little more time won’t mean anyone dying because we didn’t get there fast enough, it sounds like. So how about this: we call an expert, get you fixed up and back to normal, and _then_ we go find the witch?”

That’s a decisive yes from Cas.

Sam, however, looks skeptical. “Where are we going to find an expert?” he asks. “We haven’t heard anything from Rowena in weeks.”

“Not who I meant,” Dean says with a grin. He pulls out his phone and scrolls through his contacts, ignoring Sam’s questioning noises. “Hey, Alicia. It’s Dean. How are you? Listen, Sam and I need to ask you and Max a favour.”

“Huh,” Sam says after Dean has ended the call and is looking at him with more than a hint of smug satisfaction. “Smart.”

“I have my moments. They’re wrapping up a case but they can be here by around noon tomorrow. Alicia thinks they should be able to handle it.”

“That’s good,” Sam says, raising a hand to cover his yawn. “I’m going to head to bed, then. Nothing more we can do tonight.”

“Yeah,” Dean agrees. “See you in the morning.”

“Night, Dean.” Sam raises an eyebrow and looks down at Cas. “Night, Cas.”

Cas lifts one leg and waves it in farewell. It’s kind of adorable.

Shaking his head, Sam leaves the library. It’s quiet, but comfortably so. Dean isn’t all that tired, but Sam is right. There’s nothing more he can do tonight.

“I guess I’ll do the same,” he says to himself. “Night, Cas.”

As he turns to walk away, Cas launches himself off the table and onto Dean’s arm. Dean tenses at the shivery feeling of Cas’ tiny legs on his skin but manages not to instinctively shake him loose. 

“What, you don’t want to stay in here?” Dean laughs. “Alright, fine. Not like you take up much space, or make any noise.”

He drops Cas off in his room and waches fondly as he scurries up to what’s become his corner of the room. Dean goes down the hall to the bathroom, brushes his teeth and then returns to his room. It’s not until he’s pulling his jeans off that the realization hits him.

“Cas?” he says, a bit hesitant.

Cas drops down on a thread and dangles level with Dean’s face like he’s listening carefully. 

“Were you here last night too? I know you must have been at some point, took you awhile to make that web.”

The Yes and No notes are still on the wall from earlier, and Cas swings over to perch on Yes.

Oh. Well. Dean isn’t exactly sure how to feel about that. Warmth spreads through his entire body, some combination of embarrassment and arousal. 

“Cas,” he says again, struggling to keep his voice level, “were you in here while I was, uh, having some _private time_?”

Cas freezes, the exact way a cornered animal does when confronted with a predator. Dean sighs and pinches the bridge of his nose. “You saw that, huh,” he mutters. “Or, uh, heard.”

After another moment of stillness, Cas explodes into motion, scrambling up the wall and back into his little corner. Dean swears under his breath. “You can’t just run away from a conversation!” he yells. “God, this is worse than you zapping yourself away in the middle of an intense moment. Get back here.”

Cas doesn’t move. 

“Fine,” Dean says. “Stay up there. But just so you know, I’m not mad.”

There’s the faintest hint of movement from the corner of the room.

“Seriously,” Dean continues. “I mean, generally I prefer to know when I’ve got an audience, and I generally prefer when my audience is human. Not exactly high standards.”

He doesn’t know why he even brought this up. It’s easy to talk to Cas like this, though. Probably because he can’t say anything back, can’t stop Dean, can’t give him one of those intense looks that make Dean’s knees go weak and his words die in his throat. 

Dean remembers exactly what happened the night before. Remembers exactly whose name he said as he came. And based on today’s experiments, Cas has no trouble understanding human speech.

So there’s no point in denying anything, not anymore. Secret’s out. And Cas is still here. Okay, yeah, maybe that has more to do with him being a spider and in serious need of help than it does with any feelings he might have for Dean, but a guy can still hope. 

“So, anyway,” Dean says, feeling slightly foolish, “no repeat show tonight, sorry. But maybe, when you can actually form words and proper sentences again, it’s something we can talk about.”

He can feel the warmth rising in his own cheeks and he’s glad no one else is around to witness this conversation. “I’m sorry this whole thing got dragged out of me while you’re, you know, a spider. But we’re going to fix you, Cas, I promise.”

He glances up, and sees that Cas is busy spinning the beginning of a new web. Dean smiles at the sight. He wonders what it will say when he wakes up in the morning.

“Goodnight, Cas,” he says quietly, then turns out the lamp and climbs into bed.

***

It’s the first thing he checks when he wakes the next morning, flicking on the light and peering up into the corner of the room to see what message Cas has for him this morning. In lettering slightly less crooked than it was the day before, the web reads _I trust you_.

A warm feeling spreads through Dean’s entire body. It’s three simple words, and maybe not the three words most people would place the highest value on, but they’ve always been a bit different, he and Cas. They’ve always had a strange way of saying those other three words without actually saying them. 

But Cas trusts him to get him back to his normal body. And that’s more than enough for Dean. 

“Good morning, Cas,” he says, and is pleased when the tiny ball in the centre of the web uncurls itself in response to his greeting. “You’re getting better at the web-writing.”

He immediately regrets his words. He doesn’t want Cas to get better at being a spider, he wants Cas back the way he was before. Somewhere between angel and human, grumpy and determined, the best friend Dean has ever had.

Clearing his throat awkwardly, he reaches out his hand for Cas to jump onto. “Let’s go get ready,” he says. “This should be a big day.”

He leaves Cas in the library while he goes to shower. Old habits die hard, and he’s not certain he would remember exactly who the giant spider was if he looked up through the steam and saw him in the bathroom. He won’t risk accidentally hurting Cas. Plus, there was that whole conversation about privacy. Cas has been really taking the lack of personal space to a new level since he grew six extra legs.

Once Dean is showered and dressed, he returns to the library, where he finds Sam going over one of the books again, Cas perched beside his hand like he’s reading along. Dean stands in the doorway, a foolish grin hovering on his lips, before joining them at the table.

“Anything?” he asks.

Sam shakes his head. “No, but I’m counting on Max and Alicia. Mostly I’m just trying to pass the time until they get here.”

“Well, we’re going to need to eat,” Dean points out. “You stay here and see if you can find anything that will speed things along once back-up arrives.”

Cas scampers across the table and up Dean’s arm as he turns to head to the kitchen. Sam’s lips twitch slightly, but he wisely refrains from making any smart remarks. He knows Dean has the power to withhold breakfast if he gets too flippant.

Dean decides it’s a good day for pancakes, so he gently sets Cas down on the counter and starts gathering ingredients. “Don’t fall into the mixing bowl, okay?”

He’s treated to what he thinks is a look of disdain, then Cas nimbly climbs up the side of the cabinets and perches a safe distance away from where Dean is measuring out flour and baking powder. He hums to himself as he works, glancing up occasionally to smile at Cas, who seems content to observe him.

It’s kind of nice, this quiet moment between them. They don’t spend enough time here together, in Dean’s favourite room in the Bunker. Cas is always coming and going, never staying long enough to relax and enjoy himself, to let Dean take care of him. If only Cas could talk to him, roll those big blue eyes at some of Dean’s more outlandish statements, it would all be perfect.

“I’m going to make you pancakes someday soon,” Dean declares. 

Cas doesn’t answer, of course, but Dean smiles regardless. They just have to get Cas back to his proper size and shape, and then they can figure the rest out after that. 

Sam hasn’t found any new information. Dean really wasn’t expecting him to, but it’s frustrating, trying to wait patiently for someone else to show up and save their asses. At least, he reflects, they’re waiting for people they don’t have to feel gross about teaming up with. He likes Max and Alicia. They’re good kids, and they’re smart as hell. Between the four of them, they should be able to figure this out.

“Hey,” he says to Sam as they dig into their pancakes. “Pull up some spider videos on YouTube.”

Sam shoots him a glare. “What, and give Cas some sort of complex?”

“He’ll be fine,” Dean replies with a dismissive wave. “He doesn’t have anything to feel less than confident about, he’s got the web-writing thing down.” He flushes faintly, remembering the message Cas left him that morning, then clears his throat and continues. “Look, just give us a distraction, okay?”

Sam shakes his head, but he dutifully searches “spider videos” and angles the screen so all three of them can watch. They watch videos of giant spiders from all parts of the world, some impressive and some downright terrifying. Eventually, the suggested videos move on to other animals, and they’re all so absorbed they barely register the sound of someone knocking on the Bunker’s front door. 

Dean scrambles up the stairs, Sam following closely behind him, and throws the door open to reveal Max and Alicia smiling at him on the other side. “Hey,” he says. “Man, am I glad to see you guys.”

Max lets out a low whistle as he makes his way down the stairs, eyes roving curiously over the War Room and into the library. “Sweet,” he murmurs, immediately heading for the pile of books on the library table.

Alicia hangs back, chatting away to Sam, telling him about their drive and the last hunt they wrapped up. Dean nods in approval as she recounts the rather gruesome salt and burn. “Sounds like you need a drink,” he tells her. 

“God, yes,” she says. “But not until we get this situation of yours sorted. Then it’s shots all around.”

“I like your style,” Dean says with a grin. “Come on. Cas is in here.”

They enter the library, where Max is already combing through their books. There’s no sign of Cas.

“Cas?” Dean calls out. Where the hell did he go?

“You lost him?” Alicia says skeptically. “How did you lose him?”

Right. Dean failed to mention exactly what sort of animal Cas had been transformed into. “Umn,” he says, scratching sheepishly at the back of his neck. “He’s sort of small, at the moment.”

Max looks up, his perfectly arched eyebrows lifting in confusion. “How small?”

“He’s big for his species,” Dean says. Why he’s getting defensive, he doesn’t know. 

Sam, thankfully, takes charges of the situation. “He’s a spider.”

Alicia lets out a little shriek, then claps her hands over her mouth, looking apologetic. “Sorry,” she says. “A _spider_ , though?”

“Alicia’s not a fan,” Max says around his pleased grin, clearly unfazed by the revelation. “Oh, this is going to be good.”

“He’s a cool spider,” Dean says, patting her arm in what he hopes is a reassuring manner. “Cas, seriously, come on out. They’re here to help.”

After a tense moment of silence, Dean catches movement out of the corner of his eye and sees Cas emerge from under the table, crawling directly towards him. He places his hand on the table and let Cas perch on it, lifting it up for Max and Alicia to see. “So,” he says. “This is Castiel. Arachnid of the Lord.”

Cas raises one leg and waves it in greeting. It’s far more endearing than it has any right to be.

Max looks caught somewhere between shock and amusement, while Alicia just bites her lip and tries to summon a smile. “Well,” she says, swallowing heavily. “Now we know what we’re working with.”

“And why it’s so important to get him changed back,” Dean adds. 

“Yeah, I see the reason for urgency here,” Max says. “So, uh, Castiel. You can understand us?”

Dean sets his hand back on the table and lets Cas run over to the Yes paper. Max looks suitably impressed, but just nods and carries on. “Cool. So, Dean told me we’re pretty sure you were cursed by mistake, possibly by someone new to the whole witchcraft thing, and that the curse didn’t take hold until a few hours later?”

Cas maintains his position. Alicia moves closer, keeping a wary eye on him, but peering over her brother’s shoulder at the same time. “Why would anyone want to turn someone into a spider?” she wonders. “It’s a pretty specific curse.”

“It is pretty weird,” Max comments, still flipping idly through the book. “Some curses are meant to transform the person affected into a visual representation of their inner self, or are related to the perceived fault on the part of the witch who placed the curse in the first place.”

“So, what, some guy refused to kill the spiders for his girlfriend, so she turned him into one?” Alicia asks, eyebrows raised. “Or the other way around. You never know.”

“Honestly, we’ve dealt with weirder,” Dean chimes in. “Do we really need to know why Cas got cursed?”

“Not really,” Max says with a sigh. “But the more accurate our understanding of the situation, the more precise we can be with a counter-spell.”

It would be really helpful if Cas could talk. Dean looks at him pleadingly. “Come on, buddy,” he says. “There’s gotta be some way to get more info out of you.”

“You said he was in Cheyenne when he got hit, right?” Alicia says abruptly.

“Yes,” Sam confirms. “Is that relevant?”

“Maybe,” she says excitedly. “Max, remember Vivian?”

“I remember Vivian’s hot brother,” Max says, a dreamy look entering his eyes. Alicia rolls her eyes and whacks his shoulder, but he just pushes her away teasingly.

Dean snorts and tries to cover his smile. Their dynamic reminds him an awful lot of he and Sam. He catches his brother’s eye and grins, mouthing the word _siblings_ at him. Sam just nods in agreement.

“Anyway,” Alicia says, turning back to Sam and Dean. “There was this girl we met about a year ago, when we were living in Cheyenne for a while. Her name was Vivian, and we were good friends. She, uh, accidentally stumbled onto some of our books this one time, and we tried to cover it up, but basically, she knows who we are. What to do.”

“And she just happens to live in the same town where Cas got whammied,” Dean remarks. “Huh. You think she went digging, tried to teach herself some magic?”

“I wouldn’t put it past her,” Alicia says. “Great girl, really, but a bit…”

“Extra,” Max supplies. “As the kids are saying these days.”

Dean scoffs. Kids. Like Max isn’t one of them. “Extra enough to try to turn someone into a spider?”

“If they pissed her off enough, definitely.” Alicia nods firmly. “Okay. So, then, who knows what she found when she went looking. Probably a whole bunch of nonsense. No wonder it hit the wrong person.”

“So we don’t actually want a specific counter-spell,” Max explains, seeing the confusion on Sam and Dean’s faces. “Those are meant to complement proper spells, and amy just end up making things worse. We want to go more basic.”

“Reversion to the standard state of things,” Alicia agrees. “Pretty simple, actually.”

Sam looks skeptical. “So it doesn’t really matter that he’s a spider, we just have to focus on turning him back to how he used to be?”

“Pretty much,” Max replies. “It’s not always complicated, end-of-the-world stuff, you know.”

“It is for us,” Dean mutters. “But hey, lucky break. I’m not complaining. So, what do we need to do?”

“Stand back,” Max answers, already busily clearing the table. 

“He doesn’t really like people interfering when he’s trying to work,” Alicia explains in a low voice. 

Sam nods sympathetically. “Dean’s the same way in the kitchen.”

Dean shoots him an aggravated look, but Sam just smiles beatifically and keeps chatting to Alicia about the spell Max is preparing. 

Cas is still in the center of the table, and maybe spider body-language isn’t quite the same as human, but Dean is pretty sure he looks nervous. He approaches the table and stretches out his hand, letting Cas run over his fingers.

“Don’t worry,” he says quietly, hoping the others can’t hear him. “We’re going to get you back in no time.”

He trusts Max. He really does. But it’s still a bit hard to step back and let him take the reins. Not because of any ego or control issues, but just because it’s _Cas_. Dean has always been a bit over-protective when it comes to him. 

He’s a little bit more emotionally invested than he would be if it was some random vic who got turned into a spider, alright? He’s mature enough to accept that.

“See you on the other side,” he murmurs, and Cas carefully climbs off his hand and back onto the table.

He feels Max’s eyes on him, and Dean turns, prepared to get defensive, but he’s struck by the look of compassion on the other man’s face. “Don’t worry,” Max says quietly, squeezing Dean’s shoulder. “You’ll have your angel back in no time.”

Dean’s throat is too tight to speak, so he just nods and steps back. Sam doesn’t say anything, but he does give Dean a little smile that tells him everything he needs to know. 

Who would have guessed that after all these years, it would take Cas being turned into a spider for everything between them to be brought out into the open? 

The spell doesn’t take long at all. Max gathers some ingredients, recites a few lines of Latin, and then there’s a loud popping noise and a burst of blue-grey smoke envelops the table.

The smoke clears away to reveal Castiel, human-shaped once more, sprawled in the middle of the table. Completely naked.

And sure, maybe Dean’s had a few fantasies that started almost exactly the same way, but his brother and two others definitely weren’t present in those versions. He immediately pulls off his plaid overshirt and tosses it to Cas, who sits up, draping the shirt over his lap as he does.

“Cas?” Dean says, approaching the table. “You with us, man?”

“I believe so,” Cas answers. His voice is somehow even raspier than usual. “I have the appropriate number of limbs, at least.”

He starts to slide off the table, but nearly falls, so Dean rushes over to steady him. Cas looks up at him gratefully, and it’s sappy as hell, but Dean is just so damn glad to see those eyes again.

“You’ll probably be a bit shaky for a day or two,” Max says. “Side-effect of the transformation.”

Cas frowns. “My Grace--”

“It’ll help, I’m sure, but I wouldn’t go running a marathon anytime soon anyway,” Max advises.

After a second, Cas nods in resignation. “I do feel rather tired,” he admits.

Well, that simplifies things for Dean. “Come on,” he says, guiding Cas towards the hall. “Let’s get you to bed.”

“Thank you,” Cas calls back to Max as they shuffle out of the room.

“No worries,” Max replies. “It’ll make a great story.”

“The time we turned someone from a spider back to an angel,” Alicia says, shaking her head. “Our lives are weird.”

“Better get used to it,” Sam advises.

That’s the last of their conversation Dean hears, focused on half-carrying Cas down the hall towards somewhere with a bed. They’re just level with the door to his room when Cas stops and looks up at him, a question in his eyes.

Honestly, Dean hadn’t even been thinking of it. He thought they ought to work on getting Cas back to full strength and then work out whatever’s going on between them, but apparently Cas has other plans.

So he opens the door and guides Cas inside, pulling back the covers and letting him crawl into the bed. After a minute, Cas hands Dean his shirt back, and Dean tries not to think about how warm it is from contact with all that tan skin, tossing it into his laundry basket and swallowing roughly. 

“Try to get some rest,” he says quietly. He keeps his hands clenched tightly at his sides, because Cas is back, human-shaped and gorgeous, and he’s _naked_ in Dean’s bed, and all Dean wants to do is reach out and smooth the hair back from his forehead and hold him until he falls asleep.

He must be getting soft in his old age.

“Will you stay?” Cas asks. 

Dean pauses, already half-turned away from the bed to give Cas some peace and quiet. “What?” he says. He isn’t sure he heard him properly.

Cas has enough strength for a truly masterful eye-roll. “Dean,” he says. “Please, stay.”

Dean isn’t going to argue. He huffs a little laugh and pulls off his jeans so he’ll be more comfortable, then slides into bed beside Cas, who immediately presses himself all along Dean’s side. Dean swallows heavily and wraps a cautious arm around his shoulders-- which are a whole lot broader than he remembers, and isn’t that a delightful thought-- pulling him in closer.

Before he has a chance to say anything, there’s a gentle knock on the door. Dean looks at Cas, who doesn’t seem at all perturbed by the thought of someone seeing them like this, so Dean just takes a deep breath and calls out, “Come in!”

Sam sticks his head in, and though his eyes widen slightly at the sight before him, he refrains from commenting. “Max and Alicia think we should go track this Vivian girl down, make sure she hasn’t gotten anyone else into any kind of trouble,” he says. “I was going to ask if you wanted to come with, but…”

Part of Dean does want to go. But Cas needs to rest up, and Max and Alicia are competent enough on their own. If Sam goes with them, they’ll be fine. 

“You go,” he says. “Don’t get turned into anything weird, alright?”

“You bet,” Sam replies. He turns to leave, but then pauses, a strange smile playing around his lips. “By the way...it’s about time.”

He closes the door gently behind him, and Dean just let his head fall back onto the pillow, laughing to himself.

“What’s so funny?” Cas asks sleepily.

“You were a spider,” Dean says, still marveling at the strangeness of it all. “How freaking weird is that.”

“You’re telling me,” Cas says grumpily. “All those extra legs, not being able to communicate efficiently…”

“You did pretty well for yourself,” Dean assures him. 

“Not well enough for certain conversations we need to have,” Cas says, with a gleam in his eyes that sends a shiver down Dean’s spine. 

Dean clears his throat, prepared to launch into a discussion about their relationship, but Cas keeps talking. “You expressed an interest in knowing how I arrived here, for example.”

That was not at all what Dean was expecting. He opens his mouth, and then closes it again, unsure how to respond. Then he catches sight of the smirk playing around Cas’ lips and chuckles ruefully to himself. 

“God, you’re such a little shit,” he says. He really missed that about Cas. “But fair enough. I really do want to know how you got here.”

Cas draws back far enough that he can look down at Dean’s face as he explains. “A bird brought me.”

“A bird,” Dean repeats flatly. “What, is there some weird hitchhiking culture among birds and bugs that we humans don’t know about? You should probably call David Attenborough with that gem.”

“Not normally, no,” Cas assures him. “My ability to communicate with animals wasn’t hampered by the curse, somehow. I simply asked a bird to fly me here, and promised her a favour in return.”

“This is quite possibly the most ridiculous thing that has ever happened to us,” Dean proclaims. 

“Perhaps,” Cas agrees. “But I think we’ll look back on it fondly. Mostly because it has led to another long-overdue conversation.”

Dean swallows nervously. Judging by the way Cas’ eyes have gone both soft and serious, he’s not screwing with Dean this time. 

“Right,” he says. “That conversation.” Probably not the kind of thing he should be thinking about when he has Cas’ naked body pressed up against him, but at least it’s a human-shaped body now. 

“I meant what I said, in the web,” Cas says softly. 

“Yeah,” Dean says quietly. “I know.” He knows Cas meant more than just _I trust you_ too. 

“And you--”

“I really want to kiss you right now,” Dean admits. 

The smile that spreads across Cas’ face leaves Dean breathless. “Good,” he murmurs, one large hand reaching out to trace over Dean’s face. He moves closer, so slowly, and then finally, their lips meet.

It’s soft, surprisingly easy, like they’ve done this a thousand times before. Cas sighs into the kiss and slides even closer, so much naked skin pressed against Dean’s body that he thinks he might burst into flames from the heat of it all. 

When Cas draws back a moment later, though, it’s not another moan or fond words that spill from his mouth, but a yawn that stretches his jaw so wide it almost pops. His eyes widen, and he murmurs an apology, but Dean just chuckles and presses a kiss to his forehead.

“Don’t worry about it,” he says. “Max said you’d be feeling pretty tired. I’m not offended.”

“I am,” Cas mutters. “We’ve spent years not kissing, and I’ve been a spider for days, and now, when everything is finally the way it should be, all I can think about is sleep.”

He looks so disgruntled that Dean simply has kiss him again, but then he reluctantly draws back and manages to tuck Cas more comfortably against him. “Sleep,” he says. “There’ll be time for that once you’re back at one hundred percent.”

“There’ll be time for lots of things,” Cas says, his eyes slipping closed. “I had a lot of time to think, you know. There wasn’t much else to do these past few days.”

Well then. Dean has a feeling he’s going to be in for a wild ride over the next few days. Maybe he should send this Vivian chick a thank-you card.

“Anything you feel like sharing with the class?”

“Mmn,” Cas mumbles, already half-asleep. “I certainly learned a lot of patience. And a new respect for rope-like materials.”

“Jesus,” Dean breathes. He can picture it already, his wrists tied to the headboard...

“Something stronger than spiderwebs would be necessary, of course…”

“Of course,” Dean agrees calmly, like this whole discussion isn’t setting every nerve in his body alight. 

He waits a few more seconds, but Cas doesn’t elaborate. His eyes are closed, and his breathing has evened out. “Cas?” Dean whispers.

There’s no response. 

“Really know how to leave a guy hanging,” Dean mutters, there’s nothing but fondness in his tone. He pulls the covers more comfortably over the two of them and tightens his grip on Cas’ body.

God, it’s good to have him back. And the fact that he’s here, in Dean’s bed, in Dean’s arms, is just the icing on the cake.

“In the morning,” he tells Cas, even though he knows he can’t hear him, “I’m going to make us pancakes. Judging by that one idea...we’re going to need our energy.”

**Notes for the Chapter:**

> This is the end of the story, but you can click through to Chapter 2 for some fun art. It's not explicit, but it does contain language you may not want others to see, just as an FYI!


	2. Chapter 2

**Notes for the Chapter:**

> Bonus artwork, courtesy of [A_Diamond.](http://archiveofourown.org/users/A_Diamond/pseuds/A_Diamond)

**Author's Note:**

> This story owes a debt to the most wonderful animal transformation fic of all time, Annie D's "What Has Eight Tentacles and Isn't Allowed to Eat Pie," which taught me that you could make it cute even if the animal in question wasn't particularly fluffy. If you haven't read it, I recommend doing so immediately.


End file.
